1. Field of the Invention 
The present invention relates to wrenches, and more particularly, to a wrench stop for multipoint box-end and open-end wrenches. The wrench stop is a thin circular plate attached to the end of the wrench to prevent the wrench head from slipping off the fastener and to facilitate locating, aligning and positioning the box-end or open-end of the wrench on the bolt head or nut of a fastener being tightened or loosened. 
2. Description of the Related Art 
Wrenches in general are well known in the art for tightening or loosening fasteners which are often located in odd and difficult to see locations. One problem with existing wrenches is that the positioning and retention of the box-end or open-end wrench upon a fastener can be relatively difficult, particularly when the wrench is used to position the box-end or open-end on a nut of the fastener in restricted locations where the fastener is not easily viewed when the user is attempting to tighten or loosen the nut. 
A further problem is that when the bolt head is loosened from the workpiece or the nut is advanced along the threaded bolt shank, the head of the wrench can slip off of the bolt head or  nut, sometimes causing the user to skin or bruise the knuckles on the workpiece. In any event, when this occurs, the user must reposition the box-end or open-end of the wrench on the fastener. 
In an effort to overcome these deficiencies, there have been numerous attempts to provide a wrench structure that prevents the wrench head from slipping off or past the fastener with subsequent risk of personal injury to knuckles and hands and/or damage to both the wrench and fastener, as well as the consumption of the necessary time in re-positioning the wrench on the fastener when using the wrench. 
For example, U.S. Pat. No. 2,697,371, issued Dec. 21, 1954 to Bowman, U.S. Pat. No. 1,635,102, issued Jul. 5, 1927 to Watson, U.S. Pat. No. 4,406,188, issued Sep. 27, 1983 to Mills and U.S. Pat. No. 4,787,273, issued Nov. 29, 1988 to Griffith all describe a sliding member attached to the shank of the wrench which is slid back and forth to engage to the bolt and nut of the fastener. This arrangement is cumbersome, time consuming and not suited for use with wrenches having a non-uniform shank. These devices are not cost effective, and the sliding member may easily be damaged and become unusable after repeated use. 
U.S. Pat. No. 5,983,758, issued Nov. 16, 1999 to Tanner, describes an integral stopper located in alternating triangular areas along the circumference within the gripping portion of a socket near the shoulder to prevent slippage of the wrench past the fastener.  
U.S. Pat. No. 3,731,722, issued May 8, 1973 to Carr, describes the use of an adjustable, magnetized ringlet with a radial split inserted within the bore of a wrench gripping member, and/or use of a bendable H-shaped strip for holding the ringlet on the top of the box-end of a wrench. 
U.S. Pat. No. 2,751,802, issued Jun. 26, 1956 to Reuillard, describes a pivotal metal strip attached to a socket head for frictionally retaining the socket against the nut. 
U.S. Pat. No. 4,058,032, issued Nov. 15, 1977 to Jacks, describes an open-end wrench provided with a resilient insert means, such as a spring wire clip, inserted into the jaw for frictionally engaging the nut of a fastener. 
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus a wrench stop solving the aforementioned problems is desired. 